(BoolValue) Handle HTTP requests with absolute URLs in the requests. These requests
are generally sent by clients to forward/explicit proxies. This allows clients to configure
envoy as their HTTP proxy. In Unix, for example, this is typically done by setting the
http_proxy environment variable.

(UInt32Value) This field also acts as a soft limit on the number of bytes Envoy will buffer per-stream in the
HTTP/2 codec buffers. Once the buffer reaches this pointer, watermark callbacks will fire to
stop the flow of data to the codec buffers.

initial_connection_window_size

(UInt32Value) Similar to initial_stream_window_size, but for connection-level flow-control
window. Currently, this has the same minimum/maximum/default as initial_stream_window_size.